Pyrroloquinoline quinone (PQQ) and its derivatives are present in tissues and biological fluids at concentrations ranging from nanomolar to micormolar amounts. PQQ also elicits important physiological and developmental responses and improves growth, particularly during the neonatal period. The P.I.'s group has developed models to study the effects of PQQ deprivation. Accordingly, the primary objective of this proposal is to establish why PQQ functions as a growth factor or coenzyme in animals, and to establish why PQQ is nutritionally important during the period of neonatal development. Whether or not PQQ plays an essential role in metabolism, however, is controversial. Although there is good acceptance that PQQ has pharmacological activity, additional work is necessary to place PQQ in the category of a "conditional" nutrient., cofactor, or growth factor. The P.I.'s overall hypothesis is that PQQ or a related derivative is nutritionally important and is conditionally essential in a nutritional context. There are three principal aims: 1) to describe the physiological and nutrition effects of altered PQQ status at periods important to reproduction, lactation, and early development, 2) to determine how tissue levels of PQQ are regulated, and 3) to determine if PQQ synthesis occurs in mammalian cells. Methods are in place to permit nutritional studies at the current state of the art in this regard using chemically defined diets. Novel approaches are presented for the synthesis of radiochemically labeled forms of PQQ using plasmids containing recombinant genes for PQQ synthesis transfected into E.Coli. that are auxotrophic for PQQ precursors. Mass spectral analysis will be used to define PQQ and PQQ adducts.